1. Field of the Invention
The present invention relates to a vacuum pump having a bearing for supporting a quick-rotatable shaft, a lubricant pump having a rotor with at least one structure for producing a pumping-action, and a closed lubricant circuit in which the bearing and the lubricant pump are arranged.
2. Description of the Prior Art
Vacuum pumps with quick-rotatable components find today numerous industrial applications. In vacuum pumps designed for operation in the molecular flow region and for producing high-vacuum, the rapid rotational speed of these components lies in a range of tens of thousands revolutions per minute. In the state-of-the-art, two types of bearings are used for supporting these quick-rotatable components. To one type relate magnetic bearings which can be formed as passive or active magnetic bearing. To the other type relate precision roller bearings. A precision roller bearing requires lubrication to keep the wear as small as possible. In this case, often, close-circuit lubrication is used, and the vacuum pump includes a lubrication circuit in which there are arranged the roller bearing and a lubricant pump.
U.S. Pat. No. 7,367,429 discloses a lubricant circuit for a vacuum pump with a closed-circuit lubrication. The lubricant (oil) pump has two, oppositely extending, delivery spindles of which only one is immersed in the lubricant at a time. With such oil pumps, the oil pump bearing should be reliably supplied with lubricant. A poor supply can, however, endanger the reliability of the pump. In addition, a compact arrangement is desirable.
An object of the present invention is to provide a lubricant pump having a simple construction and a high reliability.